Heat exchangers are used in many industries to remove heat from one fluid and transfer the heat to another fluid. A variety of heat exchanger designs are available, and each basic design has many possible configurations and materials of construction. The design chosen for a specific application depends on the conditions under which the heat exchanger must operate and the function it must perform.
When the fluids passing through a heat exchanger are clean and not likely to form deposits on the heat transfer surfaces, any of the designs capable of handling the temperatures and pressures imposed by the application can be used. However, if both fluids contain particulate matter or have a tendency to form deposits on the heat transfer surfaces, the available options become limited.
Shell-and-tube heat exchangers are the workhorses of the chemical process industry, but are generally unacceptable for handling liquids containing solids on the shell side of the exchanger. The multiple tubes act similarly to a filter, and the shell side quickly plugs with the solids.
Wide-gap plate-and-frame heat exchangers can sometimes be used to transfer heat between two fluids containing particulate matter but only if the matter is not fibrous in geometry and at the expense of a very high pressure drop across the exchanger. In addition, the flow channels in a plate-and-frame heat exchanger contain many contact points between adjacent plates, which serve as points where solids begin accumulating to subsequently clog the open portions of the flow channels.
Spiral heat exchangers are most often used for this difficult application, since they are generally resistant to plugging by solids. However, they are very large and expensive compared to the other heat exchangers available. Since they are available in a limited range of sizes, off-optimum comprises are often necessary.
An object of the present invention is to provide a heat exchanger which is capable of transferring heat between any two fluids. In particular, the heat exchanger of the present invention works well for those applications where both fluids are contaminated with solids or substances which are prone to accumulate on heat transfer surfaces.
Another object of the present invention is to provide a heat exchanger which is less expensive to build than a spiral heat exchanger.
Another object of the present invention is to provide a heat exchanger which is easy to clean and maintain.
Another object of the present invention is to provide a heat exchanger which is compact in size.
Another object of the present invention is to provide a heat exchanger which can be easily customized to permit optimization of flow velocity and heat transfer surface for a variety of applications.
Another object of the present invention is to provide a heat exchanger which contains built-in provisions to permit its parts, which are typically metal, to independently expand or contract due to different temperatures without placing excessive stress or strain on the heat exchanger assembly.